Electrical connection interfaces and methods for adjacently positioned circuit components

ABSTRACT

Electrical components, such as packaged integrated circuit devices that are mountable on a substrate surface, are provided with at least one exposed electrical contact on a side surface of the component that will be substantially perpendicular to the substrate surface when the component is mounted. Two such components can be mounted side-by-side on the substrate surface with the above-mentioned contacts close to one another between the above-mentioned side surfaces. An electrical connection between the contacts can be made (or perfected) by depositing an electrically conductive connector material in contact with both of the contacts between the above-mentioned side surfaces.

BACKGROUND OF THE INVENTION

This invention relates to electronic circuitry, and more particularly tomaking electrical connections between adjacent electronic components inan assembly of such components.

Many electronic systems require multiple electronic components, such aspackaged integrated circuit devices, to be placed close together forsuch purposes as overall system compactness, electrical interconnectionsof the shortest possible length for increased signaling speed andreduced signal attenuation, etc. It is known to place such components ona printed circuit board (“PCB”), whereby input and/or output (“IO”) pinsof the components can be interconnected via printed circuit traces onthe PCB. Package-on-package (“POP”) assembly of such components is alsoknown in which, for example, a packaged integrated circuit with IO orexposed electrical contacts on its lower surface is mounted on top ofanother such component having IO pins or exposed electrical contacts onits upper surface. The lower surface contacts on the first-mentionedcomponent and the upper surface contacts on the second-mentionedcomponent are vertically aligned with one another and electricallyconnect to one another, either directly or via some conductive mediumsuch as solder, anisotropic conductive film (“ACF”), or the like.

Further improvements to techniques for interconnecting electroniccomponents in systems are needed for reasons such as the following.Component size is becoming smaller, but the number of requiredinterconnections is becoming larger. This places constraints on how manyIO contacts a component can have if contacts are confined to thetraditional locations (e.g., the bottom of a component for mounting on aPCB, and/or the top and bottom of a component that will be mounted on aPCB with another component mounted on top via POP). More ways to getsignals into and/or out of a component and to and/or from adjacentcomponents are therefore needed.

SUMMARY OF THE INVENTION

In accordance with certain aspects of the invention, a first electroniccircuit component (such as a packaged integrated circuit) is providedwith at least one exposed electrical contact along a side surface of thecomponent. A second component is similarly provided with an exposedelectrical contact along a side surface of the second component. Thefirst and second components are mountable on a substrate such as a PCBso that their sides having the exposed electrical contacts are closelyadjacent to and facing one another, and so that the exposed electricalcontacts on those sides are also closely adjacent to one another. Anelectrically conductive material such as solder, an electricallyconductive epoxy, or the like is then deposited between theabove-mentioned surfaces and in contact with the contacts toelectrically connect them.

Further features of the invention, its nature and various advantages,will be more apparent from the accompanying drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified perspective or isometric view of an illustrativeelectronic circuit component in accordance with the invention.

FIG. 2 is a simplified elevational view of a component like that shownin FIG. 1 mounted on the surface of a substrate.

FIG. 3 is a simplified elevational view like FIG. 2 showing twocomponents like the one shown in FIG. 1 mounted on the substrate surfacein accordance with the invention.

FIG. 4 is similar to FIG. 3, but shows the FIG. 3 structure afterfurther processing in accordance with the invention.

FIG. 5 is again similar to FIG. 3, but shows how the FIG. 4 conditionmay be achieved in accordance with the invention.

FIG. 6 is similar to FIG. 5, but shows a possible modification of whatFIG. 5 shows in accordance with the invention.

FIG. 7 is a simplified plan view of a structure like that shown in FIG.3 in accordance with the invention.

FIG. 8 is similar to FIG. 7, but shows the FIG. 7 structure afterfurther processing in accordance with the invention.

FIG. 9 is a simplified diagram of a material characteristic that may beprovided and utilized in accordance with the invention.

FIG. 10 is similar to FIG. 8, but illustrates a possible alternative inaccordance with the invention.

FIG. 11 is again similar to FIG. 7, but illustrates a possiblealternative in accordance with the invention.

FIG. 12 is a simplified perspective or isometric view of arepresentative portion of one component in FIG. 11 in accordance withthe invention.

FIG. 13 is similar to FIG. 11, but shows the FIG. 11 structure afterfurther processing in accordance with the invention.

FIG. 14 is again similar to FIG. 11, but shows a possible alternative inaccordance with the invention.

FIG. 15 is similar to FIG. 14, but shows the FIG. 14 structure afterfurther processing in accordance with the invention.

FIG. 16 is a simplified elevational view showing another possiblecontext in which the invention may be employed.

FIG. 17 is a simplified elevational showing another illustrativeembodiment of employment of the invention.

FIG. 18 is a simplified elevational view showing another illustrativeembodiment of the invention.

FIG. 19 is a simplified perspective or isometric view of anotherillustrative structure in accordance with the invention.

FIG. 20 is a simplified cross-sectional view showing use of structureslike what is shown in FIG. 19 in accordance with the invention.

FIG. 21 is a view similar to FIG. 19 for another illustrative structurein accordance with the invention.

FIG. 22 is a simplified elevational view showing use of a structure likewhat is shown in FIG. 21 in accordance with the invention.

FIG. 23 is a simplified perspective or isometric view showing anotherillustrative embodiment of the invention.

FIG. 24 is a simplified sectional view showing a representative portionof structure like that shown in FIG. 23 in accordance with theinvention.

DETAILED DESCRIPTION

An illustrative circuit component 10 in accordance with the invention isshown in FIG. 1. Circuit component 10 may be a packaged integratedcircuit chip or device. Only the external surface of component 10 isvisible in FIG. 1, and indeed FIG. 1 shows component 10 upside down.Component 10 is basically a right parallelepiped, i.e., a six-sidedsolid object, each side of which is a rectangle (the word rectangle alsoincluding square as a possibility). Thus component 10 has a rectangularbottom surface 20, a rectangular side surface 30 a, another rectangularside surface 30 b, two more rectangular side surfaces that are notvisible in FIG. 1, and a rectangular top surface that is also notvisible in FIG. 1.

Most of the external surface of component 10 is made of anon-electricity-conducting material (which may also be referred to as anelectrical insulator or just an insulator). Inside this external packagematerial, component 10 typically has an integrated circuit device thatis not visible in FIG. 1. However, electrical circuits on this internalcircuitry are electrically connected to electrical contacts such as 22and 32 that are exposed on the outside of component 10. Contacts 22 and32 constitute the means by which electrical signals can be applied toand/or output from the circuitry that is inside the external package20/30 of component 10. Although contacts 22 and 32 are all shown assimple squares on the various surfaces 20 and 30 of the componentpackage, it will be understood that these contacts can be of variousforms and shapes. For example, they can be flush with the associatedsurface 20 or 30; or they can be raised above that surface; or they canbe recessed below that surface; they can be in the form of outwardlyprojecting pins (perpendicular to the associated surface); and/or theycan have various shapes such as square, rectangular, circular,hexagonal, octagonal, oval, or any other desired shape.

Contacts 22 are conventionally located on the bottom surface ofcomponent 10 for conventional connection, e.g., to various circuittraces on a printed circuit board (“PCB”). Such connections may be made,for example, by or with the aid of solder between contacts 22 and thePCB traces. FIG. 2 shows such conventional surface mount assembly(“SMA”) of component 10 on PCB 100.

Unlike contacts 22, contacts 32 are not conventionally located. Rather,contacts 32 are non-conventionally located (in accordance with thepresent invention) on one or more sides 30 of the component package thatwill be substantially perpendicular to the surface of the substrate(e.g., PCB 100 in FIG. 2) on which component 10 is or will be mounted.FIG. 3 shows an example of how these side contacts 32 can be used inaccordance with the inventions.

In FIG. 3 two components 10 a and 10 b (each of which can generally belike component 10 in earlier FIGS.) are mounted in close, side-by-sideproximity to one another on the upper surface of PCB 100. In particular,each of components 10 a and 10 b has a side surface (30 x and 30 y,respectively) that is close to and faces toward the similar side surfaceof the other component. Thus, surfaces 30 x and 30 y are (1) bothsubstantially perpendicular to the upper surface of PCB 100, (2)parallel to one another, (3) facing toward one another, and (4)separated from one another by a relatively small distance. In addition,each of surfaces 30 x and 30 y has on it or in it at least one exposedelectrical contact 32 x or 32 y like any of the contacts 32 describedabove in connection with the earlier FIGS. Contacts 32 x and 32 y arepreferably aligned with one another along an axis that is perpendicularto surfaces 30 x and 30 y. Contacts 32 x and 32 y may be spaced from oneanother by a small space as shown in FIG. 3 (although such spacing canbe eliminated if desired). Any spacing between contacts 32 x and 32 y ispreferably no more than 1.0 mm, more preferably no more than 0.5 mm,most preferably no more than 0.25 mm.

As shown in FIG. 4, after components 10 a, 10 b, and 100 have beenassembled as shown in FIG. 3, electrical connection between contacts 32x and 32 y is made (or at least reinforced) by adding an electricallyconductive substance between and/or around those contacts, e.g., asshown at 40 in FIG. 4. Examples of materials that are suitable formaking connection 40 are solder, an electrically conductive epoxymaterial (e.g., an epoxy resin that is loaded with conductive metalparticles that can contact on another and form a good electricalconductor over at least a short distance through the cured epoxy resin),or the like.

FIG. 5 shows an illustrative embodiment of how conductive connectionmaterial 40 may be introduced between components 10 a and 10 b to formor perfect the electrical connection between contacts 32 x and 32 y asshown in FIG. 4. As shown in FIG. 5, a syringe or syringe-likeinstrument 200 is positioned vertically above the gap between surfaces30 x and 30 y, and also vertically above contacts 32 x and 32 y.Conductive connection material 40 in a fluid state is then forced out ofthe lower end of the hollow tube of instrument 200 and flows downbetween surfaces 30 x and 30 y and into contact with contacts 32 x and32 y. For example, during such flow, conductive connection material 40may be molten solder or uncured resin so that it can flow. Upon reachingcontacts 32 x and 32 y, the fluid material 40 hardens (e.g., the moltensolder cools or the uncured resin cures) to a solid so that it remainsin place as shown in FIG. 4.

FIG. 6 shows an alternative in which the lower end of instrument 200 isable to enter the space between surfaces 30 x and 30 y and thereby geteven closer to contacts 32 x and 32 y as it ejects conductive connectionmaterial 40 onto the contacts.

Use of syringe-like instrument 200 to get conductive connection material40 into contact with contacts like 32 x and 32 y is only an example ofhow this can be done, and any other suitable means may be used insteadif desired.

FIG. 7 is a top view of structures that can be like what is shown in anyof the earlier FIGS. FIG. 7 shows how multiple contacts 32 on theadjacent sides 30 x and 30 y of components 10 a and 10 b can line upwith one another and be used (with the addition of conductive connectionmaterial 40 as shown in FIG. 8) to provide electrical connectionsbetween components 10 a and 10 b. For example, exposed electricalcontact 32 x 1 on the side surface 30 x of component 10 a mounted on PCB100 lines up with exposed electrical contact 32 y 1 on the side surface30 y of component 10 b also mounted on PCB 100. Contacts 32 x 2 and 32 y2 similarly line up with one another between surfaces 30 x and 30 y, asdo contacts 32 x 3 and 32 y 3. To make or perfect the electricalconnection between each of these aligned pairs of contacts, conductiveconnection material 40 is applied to each such pair as shown in FIG. 8(e.g., in any of the ways shown and described above). The number ofpairs of contacts 32 x and 32 y between components 10 a and 10 b that isshown in FIGS. 7 and 8 (i.e., three pairs of contacts) is only anexample, and it will be understood more such pairs or less such pairscan be provided if desired.

If desired, conductive connection material 40 can have an electricalresistance characteristic like that shown in FIG. 9. This is acharacteristic in which resistance of the material is very low acrossshort distances through the material, but very high for significantlylonger distances through the material. For example, FIG. 9 shows thatthe resistance through material 40 is very low for distances throughthat material of about 1 mm or less, but that resistance through thematerial increases greatly for distances greater than about 1 mm. Epoxyresin conductive connection material can be formulated to have this kindof a characteristic, e.g., by appropriately selecting such parameters asthe size of the conductive particles in the resin matrix, the proportionof conductive particles to resin matrix, etc.

A conductive connection material 40 having a resistance characteristiclike that shown in FIG. 9 can be used on multiple contact pairs asshown, for example, in FIG. 10. As FIG. 10 shows, with this type ofmaterial 40 it is not necessary to physically separate the material 40that connects each pair of contacts (e.g., 32 x 1 and 32 y 1) from thematerial 40 that connects other pairs of contacts (e.g., 32 x 2 and 32 y2). The distance between the contacts in each pair is less than thedistance at which resistance through material 40 becomes very large.Material 40 is therefore a good conductor of electricity between thecontacts in each aligned pair of contacts (e.g., like 32 x 1 and 32 y1). On the other hand, the distance between contacts 32 that are notaligned in a pair (e.g., the distance between contacts 32 x 1 and 32 x2) is great enough that material 40 is not a good conductor ofelectricity between such not-aligned contacts. Accordingly, FIG. 10shows that one continuous mass or body of material 40 can be applied toall of the contacts between surfaces 30 x and 30 y, and the result willbe that effective electrical connections are only made between thecontacts in each aligned pair of contacts (e.g., 32 x 1 and 32 y 1) andnot between contacts that are in different ones of such pairs (e.g.,material 40 does not produce a short-circuit connection between contacts32 x 1 and 32 x 2 because those contacts are too far apart).

Components like 10 a and 10 b may be given surface features in thevicinity of contacts 32 to facilitate the introduction of material 40into proximity to those contacts and/or to help keep material 40confined to particular areas and away from other structures. An exampleof this principle is shown in FIG. 11, which is otherwise a viewgenerally like FIG. 10.

As shown in FIG. 11 (and also FIG. 12, which shows a representativeportion of what is shown in FIG. 11 from another perspective), the sidesurface of each of components 10 a and 10 b having side contacts 32 isrecessed (at 34) adjacent each of those contacts. When the sides 30 xand 30 y of components 10 a and 10 b are put together, these recesses 34create separate or relatively separate openings between the twocomponents. Each of these openings can be filled (or more or lessfilled) with conductive connection material 40 without that materialbeing able to extend from one opening to other openings (see FIG. 13).Between the pairs of facing recesses (e.g., between recess pair 34 xy 1and recess pair 34 xy 2) component package surfaces 30 x and 30 y can besufficiently close to one another (or even in contact with one another)to prevent material 40 in the fluid state (i.e., during deposit intoeach recess pair 34 xy) from flowing significantly beyond that recesspair (e.g., to reach contacts 32 in the next adjacent recess pair(s)).This helps ensure physical separation and therefore electrical isolation(insulation) of each connected pair of contacts 32 from all of the othercontacts 32.

FIG. 14 shows another example of modification of component packagesurface shapes in accordance with this invention. In FIG. 14 sidesurface 30 x of component 10 a can be like what is shown in FIGS. 11-13for that component. It therefore includes a recess 34 in its sidesurface 30 x for each of its contacts 32 x (i.e., each of contacts 32 xis located in a respective one of recesses 34 x). Component 10 b, on theother hand, has a raised protuberance 36 on its side surface 30 y ateach of its contacts 32 y. Each of protuberances 36 y can fit at leastpart way into a respective one of apertures 34 x. The closeness and/ortightness of this fit can be designed as desired. This type of matingstructure can again help to confine subsequently deposited conductiveconnecting material 40 to separate regions that are respectivelyadjacent each pair of facing contacts (e.g., 32 x 2 and 32 y 2) (seeFIG. 15).

FIG. 16 illustrates how the invention may be used in the context of astack of PCBs. The lower part of FIG. 16 can be like what is shown inany of many of the earlier FIGS. (e.g., like FIG. 4). PCB 100 isconnected to another PCB 300 above it by a plurality of vias 320. Othercomponents (e.g., other packaged integrated circuit devices) 310 a and310 b can be mounted on PCB 300.

FIG. 17 illustrates how the invention may be used in the context of POPassembly of some components. Again, the lower part of FIG. 17 can belike what is shown in any of several of the earlier FIGS. (e.g., likeFIG. 4). FIG. 17 then shows the addition of another component 310 c(e.g., another packaged integrated circuit device) on top of component10 a using POP techniques.

FIG. 18 shows extension of what is shown in FIG. 17 to include twolayers of application of the present invention. Once again, the lowerportion of FIG. 18 may be as described earlier. After those components(100, 10 a, 10 b, and 40 a) have been assembled, a separator 330(typically of an insulating material) may be placed above the facingside surfaces of components 10 a and 10 b. POP is then used to assemblecomponents 310 c and 310 d on top of components 10 a and 10 b,respectively. In this case, components 310 c and 310 d are likecomponents 10 a and 10 b, in that they have exposed electrical contactson their side surfaces that face one another. Conductive connectingmaterial 40 b is then deposited in contact with each adjacent pair ofsuch side contacts on components 310 c and 310 d to electrically connectthe contacts in each such pair. Separator 330 keeps material 40 b fromflowing down to structures below the level of POP components 310 c and310 d.

FIG. 19 shows another example of a geometry that may be used to helpcontrol the deposit of conductive connection material 40 in proximity topairs of side contacts that need to be connected in accordance with theinvention. As shown in FIG. 19, representative exposed contact 32 isdisposed in a recess 34 in the side surface 30 of component package 10.In this case, however, recess 34 does not extend all the way to thebottom surface of component 10. Instead, the portion 38 of side surface30 below recess 34 is not recessed. Accordingly, when side 30 ofcomponent 10 is placed close to the side of another component, a wellwith a bottom is formed. An example of this is shown in FIG. 20 in whichtwo component 10 a and 10 b (each as shown in FIG. 19) are placed sideby side. Recesses 34 x and 34 y then collectively form a well, butunrecessed surface portions 38 x and 38 y come closer together so thatthe well effectively has a bottom that is above the bottom-most surfacesof components 10 a and 10 b. (FIG. 20 is a cross-sectional view throughcomponents 10 a and 10 b at the location of the contacts 32 x and 32 ythat are in the above-mentioned well.) Then when conductive connectionmaterial 40 is deposited in contact with contacts 32 x and 32 y, thatmaterial is confined to the above-mentioned well. It is prevented fromflowing down from the well by the bottom of the well (38 xy), and it isprevented from flowing sideways (e.g., into other wells) by the sides ofthe well. A feature like this can be used immediately above PCB 100 inany of the earlier FIGS. (to keep material 40 off the PCB), and/or itcan be used in POP layers (to keep material 40 from flowing down tostructures below). In the latter case, for example, it may render theprovision of a separate separator like 330 in FIG. 18 unnecessary.

FIG. 21 illustrates the point that the principle shown in FIGS. 19 and20 is not limited to providing separate wells for each contact pair.Thus FIG. 21 shows the upper portion 34 of side surface 30 recessed, andseveral contacts 32 in that recess. Below this recess, side surface 30is not recessed (as shown at 38). When two such components 10 are puttogether, unrecessed portion 38 of side surface 30 will be close enoughto the other component to prevent material 40 from flowing down to anystructure below. FIG. 22 further illustrates this point, and furthershows that only one of the components (i.e., 10 a in this example) needsto have such a partially recessed side surface 30 x. The facing sidesurface 30 y of the other component 10 b can have another shape (e.g.,unrecessed or flat) to cooperate with unrecessed surface 38 x andthereby form a channel with a bottom that retains material 40 and keepsit from flowing to any structure below.

FIGS. 23 and 24 illustrate application of the invention to a so-calledembedded device structure. This structure includes substrate 100 (e.g.,a PCB), at least one other generally similar structure 400 (e.g., one ormore other layers of PCB structure) on top of substrate 100 but havingan aperture with sides 430 that are substantially perpendicular to theupper surface of substrate 100, and component 10 (e.g., a packagedintegrated circuit device) disposed on substrate 100 in the aperture instructure 400. Component 10 has at least one exposed electrical contact32 on at least one of its sides 30 that is substantially perpendicularto the upper surface of substrate 100. Structure 400 also has at leastone exposed electrical contact 432 on at least one of the sides 430 ofthe aperture through that structure. When component 10 is mounted in theaperture in structure 400, above-mentioned contacts 32 and 432 form anadjacent, facing, and generally aligned pair of contacts that can beelectrically connected to one another by depositing conductiveconnection material 40 in contact with them as shown in FIG. 24. Thiscan be done for any number of layers of circuitry in structure 400. Anyof the principles illustrated in earlier FIGS. can be applied again toapplications like those illustrated by FIGS. 23 and 24.

As was mentioned above, it is generally preferred that the distancebetween the contacts in a pair of contacts that are to be connected inaccordance with this invention (e.g., two contacts 32, or a contact 32and a contact 432) be relatively small (i.e., no more than 1.0 mm, morepreferably no more than 0.5 mm, most preferably no more than 0.25 mm).

It will be understood that the foregoing is only illustrative of theprinciples of the invention, and that various modifications can be madeby those skilled in the art without departing from the scope and spiritof the invention. For example, the numbers of contact pairs that areprovided and connected in accordance with the invention can be differentfrom the numbers shown in the various FIGS. herein. Also, although theFIGS. herein frequently show only two components 10 connected to oneanother by the invention in any given plane, it will be understood thatmore than two components in a plane can be connected to one another bythe invention. For example, three components can be connected to oneanother in a straight line or an L on substrate 100; four components canbe connected to one another in a square, a line, an L, or a T onsubstrate 100; etc.

1. An electrical circuit assembly comprising: a substrate surface; afirst packaged integrated circuit component mounted on the substratesurface and having a first side surface that is substantiallyperpendicular to the substrate surface, the first component furtherhaving a first exposed electrical contact on the first side surface; asecond packaged integrated circuit component mounted on the substratesurface and having a second side surface that is substantiallyperpendicular to the substrate surface, the second component furtherhaving a second exposed electrical contact on the second side surface,the first and second components being positioned on the substratesurface so that the first and second surfaces face toward one another,and so that the first and second contacts are within 1.0 mm of oneanother between the first and second surfaces; and an electricallyconductive connector material that has been deposited in contact withthe first and second contacts between the first and second surfaces. 2.The assembly defined in claim 1 wherein the first side surface isrecessed from another portion of that surface at the location of thefirst contact.
 3. The assembly defined in claim 1 wherein the first sidesurface is raised from another portion of that surface at the locationof the first contact.
 4. The assembly defined in claim 1 wherein thesubstrate surface comprises a surface of a printed circuit board.
 5. Theassembly defined in claim 1 further comprising: a third packagedintegrated circuit component mounted on the first component and having athird side surface that is substantially perpendicular to the substratesurface, the third component further having a third exposed electricalcontact on the third side surface; a fourth packaged integrated circuitcomponent mounted on the second component and having a fourth sidesurface that is substantially perpendicular to the substrate surface,the fourth component further having a fourth exposed electrical contacton the fourth side surface, the third and fourth components beingpositioned on the first and second components so that the third andfourth surfaces face toward one another, and so that the third andfourth contacts are within 1.0 mm of one another between the third andfourth surfaces; and an electrically conductive connector material thathas been deposited in contact with the third and fourth contacts betweenthe third and fourth surfaces.
 6. The assembly defined in claim 5further comprising: a separator below the third and fourth surfaces. 7.The assembly defined in claim 1 wherein the connector materialcomprises: solder.
 8. The assembly defined in claim 1 wherein theconnector material comprises: epoxy resin.
 9. The assembly defined inclaim 1 wherein the first and second contacts are within 0.5 mm of oneanother.
 10. The assembly defined in claim 1 wherein the first andsecond contacts are within 0.25 mm of one another.
 11. A method ofmaking an electrical circuit assembly comprising: providing a substratesurface; providing first and second packaged integrated circuitcomponents having respective first and second side surfaces andrespective first and second exposed electrical contacts on the first andsecond surfaces; mounting the first and second components on thesubstrate surface so that the first and second surfaces aresubstantially perpendicular to the substrate surface and so that thefirst and second surfaces face toward one another with the first andsecond contacts no more than 1.0 mm from one another between the firstand second surfaces; and depositing electrically conductive connectormaterial in contact with the first and second contacts between the firstand second surfaces.
 12. The method defined in claim 11 wherein thedepositing comprises: introducing the electrically conductive connectormaterial into contact with the first and second contacts while thematerial is in a flowable fluid form.
 13. The method defined in claim 12further comprising: allowing the electrically conductive connectormaterial to solidify from the flowable fluid form after it is in contactwith the first and second contacts.
 14. The method defined in claim 11wherein the first surface is recessed to provide a recess at thelocation of the first contact, and wherein the depositing comprises:introducing the electrically conductive connector material into therecess.
 15. The method defined in claim 12 wherein the recess is open toa top surface of the first component, and wherein the introducingcomprises: flowing the electrically conductive connector materialdownwardly into the recess past the top surface.
 16. The method definedin claim 11 further comprising: mounting third and fourth packagedintegrated circuit components on top of the third and fourth components,respectively; the third and fourth components having respective thirdand fourth side surfaces and respective third and fourth exposedelectrical contacts on the third and fourth surfaces; the third andfourth side surfaces being substantially perpendicular to the substratesurface and facing toward one another with the third and fourth contactsno more than 1.0 mm from one another between the first and secondsurfaces; and depositing electrically conductive connector material incontact with the third and fourth contacts between the third and fourthsurfaces.
 17. The method defined in claim 16 further comprising:introducing a separator below the third and fourth surfaces prior todepositing the material in contact with the third and fourth contacts.18. An electrical circuit assembly comprising: a substrate surface; afirst packaged integrated circuit component mounted on the substratesurface and having a first side surface that is substantiallyperpendicular to the substrate surface, the first component furtherhaving a first exposed electrical contact on the first side surface; asecond circuit component mounted on the substrate surface and having anaperture through it in which the first component is disposed, theaperture having a second side surface that is substantiallyperpendicular to the substrate surface, the second component furtherhaving a second exposed electrical contact on the second surface within1.0 mm of the first contact; and an electrically conductive connectormaterial that has been deposited in contact with the first and secondcontacts between the first and second surfaces.
 19. The assembly definedin claim 18 wherein substrate surface comprises a surface of a printedcircuit board.
 20. The assembly defined in claim 18 wherein the secondcomponent comprises a printed circuit board.
 21. The assembly defined inclaim 18 wherein the first and second contacts are within 0.5 mm of oneanother.
 22. The assembly defined in claim 18 wherein the first andsecond contacts are within 0.25 mm of one another.
 23. A method ofmaking an electrical circuit assembly comprising: providing a substratesurface; mounting a first packaged integrated circuit component on thesubstrate surface, the first component having a first side surface thatis substantially perpendicular to the substrate surface and that has onit a first exposed electrical contact; mounting a second circuitcomponent on the substrate surface, the second component having anaperture through it in which the first component is disposed, theaperture having a second side surface that is substantiallyperpendicular to the substrate surface and that has on it a secondexposed electrical contact within 1.0 mm of the first contact; anddepositing electrically conductive connector material in contact withthe first and second contacts between the first and second surfaces. 24.The method defined in claim 23 wherein the depositing comprises:introducing the electrically conductive connector material into contactwith the first and second contacts while the material is in a flowablefluid form.
 25. The method defined in claim 24 further comprising:allowing the electrically conductive connector material to solidify fromthe flowable fluid form after it is in contact with the first and secondcontacts.